BUG #10736: Database does somtimes not startup again after restart

The following bug has been logged on the website:

Bug reference: 10736
Logged by: Marcel Hanke
Email address: marcel(dot)hanke(at)1und1(dot)de
PostgreSQL version: 9.1.13
Operating system: Debian
Description:

After an update of any related Packet (or the postgres it self), witch
requires an restart of the Database, the db sometimes doesn't start up
again.
The Postgres is used to provide data to an Powerdns Server and runs in an
Master-Slave replication.

Errormassages:
postgres_main[3195]: [1-1] 2014-06-20 12:59:07 CEST FATAL: the database
system is starting up
postgres_main[3196]: [1-1] 2014-06-20 12:59:07 CEST FATAL: the database
system is starting up
pdns[3061]: gpgsql Connection failed: Unable to connect to database, connect
string: dbname=pdns user=postgres host=127.0.0.1 port=5432
password=<HIDDEN>: FATAL: the database system is starting up
pdns[3061]: Caught an exception instantiating a backend: Unable to launch
gpgsql connection: Unable to connect to database, connect string:
dbname=pdns user=postgres host=127.0.0.1 port=5432 password=<HIDDEN>: FATAL:
the database system is starting up
pdns[3061]: Cleaning up

The Error doesn't accrue every time. It's atm not possible to reproduce the
error on an test system, so I can't provide an debug log.

The configuration of the relevant postgres is mostly standard.
Replitation Config:
unix_socket_directory = '/var/run/postgresql'
hot_standby = on

Greetings Marcel